When Watson is implicated in a DEA investigation into doctors writing illegal prescriptions, she and Holmes search for the person using her medical license to sell drugs.

The police call in Holmes and Watson to consult on a homicide “heard” by a cutting edge gunshot detection system when they can’t find any tangible evidence that a crime was committed. Also, Sherlock and Joan become suspicious of Shinwell when he’s the target of a drive-by shooting that reveals a connection between him and an unsolved murder.

Sherlock and Joan question how well they know Shinwell when they investigate the possibility he may have gotten away with the unsolved murder of his friend, a fellow gang member. Also, Sherlock and Joan’s latest case puts them on the hunt for a treasure map rumored to lead to a fortune in pirate’s gold hidden around New York City.

When Holmes and Watson investigate a murder, they find themselves in the crosshairs of one of New York City's deadliest gangs. Holmes' behavior becomes increasingly erratic when he secretly interacts with a mysterious woman.